Why do oddities appear in the issuance of https when everything works through a proxy?

Question

Node.js

The meaning of such a node is sending a request to a server via https through a proxy. Everything seems to be excellent. But for some reason, some oddities appear in the http output structure. There is also a scheme: headers, an empty line and html itself. I have:

Headers
An empty string
Then some random number, or a number with letters (1B00). So what are these numbers? Because of this, I can't parse gzip.
Further html itself

Answer 1

Even if there is a number before the doctype html without a proxy